1. Field
Example embodiments relate to an alignment master glass for tensioning a vapor deposition mask, a method for manufacturing the same, and a method for tensioning the vapor deposition mask using the same. More particularly, example embodiments relate to an alignment master glass for tensioning a vapor deposition mask for depositing an organic emissive layer of an organic light emitting display device, a method for manufacturing the same, and a method for tensioning the vapor deposition mask using the same.
2. Description of the Related Art
Recently, electroluminescent (EL) devices regarded as self-luminous type display devices have been receiving a lot of attention as next-generation display devices due to, e.g., a wide viewing angle, good contrast, and rapid response characteristics. For example, an organic EL device may include a series of first electrodes formed as a predetermined pattern on a transparent insulating substrate, an organic emissive layer formed on the transparent insulating substrate by vacuum deposition, and a series of second electrodes formed on the organic emissive layer to act as a cathode electrode intersecting the first electrodes.
In the manufacture of an organic EL device having such a structure as described above, the first electrodes may be patterned by wet etching, e.g., a photolithography method. However, when a photolithography method is applied to etch the second electrodes, liquid may permeate into the interface between the organic emissive layer and the second electrodes, while the resist used is stripped off and the second electrodes are etched, thereby degrading the performance and lifetime characteristics of the organic EL device. For example, if the wet etching process is performed after at least a portion of the organic layer is formed, moisture may penetrate into or remain in the organic layer during the wet etching process, thereby noticeably deteriorating the performance and lifespan characteristics of the completed organic EL device.
In view of the above, the organic layer, i.e., the emissive organic layer implementing a predetermined color, and the second electrodes formed on the organic layer may be patterned, e.g., micro-patterned, by deposition. For example, the deposition method may include use of a mask with a series of long slits spaced a predetermined distance apart in its main thin plate. In another example, the deposition method may use a mask of a metal thin plate having a slit portion and a bridge portion in a mesh pattern.
In yet another example, the deposition method may use a support frame fixed to a metal thin plate, e.g., a vapor deposition mask, with tension applied to the metal thin plate, e.g., via adhesive or welding. For example, referring to FIG. 1, tension may be applied using a tensioning device to a vapor deposition mask 1, which includes a plurality of openings 3 on a substrate 2, so material may be deposited through the openings 3 to form a desired pattern. However, despite adhesion between the metal thin plate and a substrate, the openings in the metal thin plate may sag away from the substrate by the weight of the metal thin plate, even though the edges of the metal thin plate may be supported under tension by a frame. In addition, thermal expansion of the mask due to a rising temperature during formation of an organic film may facilitate the sagging of the openings.